The present invention relates to a method and apparatus for retrofitting a filtration system underdrain.
The present invention is primarily useful for retrofitting a Bell bottom underdrain, Wheeler underdrain, or any other depression-type underdrain. These types of underdrains are used in water filtration systems. In general, underdrains are used to support filtration media including such media as layers of sand, gravel, and anthracite. Water flowing through the filtration medium is purified and collected by the underdrain. The underdrains are also designed to allow water to be reverse injected (i.e, upwardly through the filtration medium) for periodic cleansing of the filtration medium as discussed below.
The present invention provides a cost-effective method/apparatus for retrofitting an underdrain such as a Bell bottom or Wheeler underdrain. In the past, when glass caps in the Bell bottom underdrain broke or became inoperable, the underdrain had to be torn out and replaced with a different type of underdrain. Replacement of the Bell bottom underdrain was required because the glass caps used in the Bell bottom underdrain are no longer commercially available. Similarly, when ceramic balls in the Wheeler underdrain were damaged, the balls had to be replaced at great cost or the underdrain had to be torn out and replaced. These replacement procedures are obviously expensive and time-consuming. The present invention provides a method and apparatus for retrofitting a filtration system underdrain, such as a Bell bottom or a Wheeler underdrain, obviating the need for replacement of the underdrains.
Additional features and advantages of the invention will become apparent to those skilled in the art upon consideration of the detailed description below and of illustrated embodiments exemplifying the best mode of carrying out the invention as presently perceived.